Mechanical and electrical characterization of carbon nanofibers produced from water soluble precursors

Abstract

This study presents the thermo-physical, electrical, and mechanical characterization of fine carbon fibers produced from water-soluble polymer precursors and low temperature processes. These fibers were developed utilizing the Forcespinning® technology which utilizes centrifugal force to spin fibers. Polyvinyl alcohol was used as the precursor material, and fibers were developed and deposited in a non-woven configuration. The resultant nonwoven fiber mats were subjected to a dehydration process through exposure to sulfuric acid vapors. The partially carbonized mats were heat treated at 850 °C. The produced porous nonwoven carbon fiber based mats have micro-and mesoporosity with a final fiber average diameter of 191 nm. The electrical volume resistivity of the polymeric nanofibers was 8×10 14 Ω•cm and it dropped to 165 Ω•cm for the chemically treated carbon fiber mat and to 0.407 Ω•cm for the subsequently heat treated fibers. The electromagnetic (EMI) shielding effectiveness (SE) was observed to be 20 and 40 dB for the chemically treated fibers and heat treated fibers respectively. The tensile stress for the chemically treated fibers was 43 MPa with a strain of 18% while the subsequently heat-treated fibers exhibited a stress of 124 MPa and strain of 21%.

Electrical Properties and Electromagnetic Interference Shielding Effectiveness of Interlayered Systems Composed by Carbon Nanotube Filled Carbon Nanofiber Mats and Polymer Composites

“…According to the literature, the obtained electrical conductivity values are considered low to satisfy EMI shielding related applications [ 35 , 36 , 37 ]; though, electrical conductivity is not the absolute criterion to shield EMI [ 4 , 38 ]. EMI is attenuated by three major mechanisms: reflection, absorption, and multiple reflections.…”

A Device for Studying the Thermophysical Properties of Bulk Textile Materials and Their Packages by the Regular Mode Method in Air

“…In the device, heat transfer between the surface of the material and the air is carried out by convective heat transfer, and inside the package between the outer layers by heat conduction. The Fourier law and numerical methods for solving heat conduction problems are used in the calculations (Mikheev and Mikheeva, 1977;Carslaw et al 1959;Cremar et al, 2016). Fourier law under stationary thermal conditions (Equation 1).…”

“…For their fastening in the case above and below there are holes in the form of a truncated cone with a curvilinear generatrix: through the upper hole (6) cold air is supplied from the hairdryer in cooling mode, and a heated air stream (from the hairdryer during heating mode is supplied through the lower hole (7)). The power consumption of hairdryers is measured using electronic power meters (11) and (12). The temperature on the surface of the sample is recorded by contact temperature sensors, thermocouples (10), (15).…”

In Situ Production of Graphene–Fiber Hybrid Structures

“…Deionized water (DI water, 18 MΩ cm) was produced from Mill-Q (Millipore Ltd., U.K.). A solution consisting of 15 wt % PVA and 5 wt % sodium chloride in deionized water was prepared with the aid of magnetic stirring at 70 °C for 5 h. The solution was subjected to Forcespinning at 7000 rpm and different times depending on the desired grams per square meter (specifics on this production method had been reported elsewhere). The obtained nonwoven nanofiber mats were then exposed to sulfuric acid vapor by placing them 5 cm above a heated bath (temperatures of up to 280 °C) of sulfuric acid.…”